Message:

<p>[QUOTE=&quot;S. Porter, post: 3200440, member: 86735&quot;]Using a neodymium magnet ($6 from Amazon), I checked my ancient bronze coins.&nbsp; Several could be picked up onto the magnet, and many more reacted slightly.</p><p><br /></p><p>The coins that the magnet picked up include Lydia/Sardis, Thrace/Rhoemetalkes, Caracalla, Philip, Constantine, Constantius II, Jovian, Valens, and a tiny late Roman (Arcadius-ish).[ATTACH=full]828170[/ATTACH]</p><p><br /></p><p>And an obvious fourree of Caracalla.</p><p>[ATTACH=full]828172[/ATTACH] </p><p><br /></p><p>Also several from the junk box.</p><p>[ATTACH=full]828173[/ATTACH] </p><p><br /></p><p>Apparently, magnetism in ancient bronzes is not a sign of a fake coin (except for fourrées with iron or cobalt in their cores), but rather occurs because bronze coins could contain a range of metals.</p><p><br /></p><p>A Coin Talk search for “magnetic” shows references to magnetic coins scattered in threads about individual coins. In one thread, Mike Margolis linked to a thorough discussion in ForumAncientCoins, which states:</p><p><br /></p><p>“I did find it interesting at first just to realize some of the bronzes were &#039;magnetic&#039; at all.&nbsp; …&nbsp; It wasn&#039;t so much a matter of being &#039;pure&#039; or &#039;impure&#039;, rather the specific metals making up the bronze <a href="http://www.forumancientcoins.com/numiswiki/view.asp?key=alloy" target="_blank" class="externalLink ProxyLink" data-proxy-href="http://www.forumancientcoins.com/numiswiki/view.asp?key=alloy" rel="nofollow">alloy</a> and their proportions.&nbsp; The ranges of alloys in ancient bronze coins is highly variable to begin with.&nbsp; The presence of enough iron and cobalt to make a bronze &#039;magnetic&#039; is fairly unusual, but those coins aren&#039;t necessarily more &#039;impure&#039; than others with lead or other peculiar <a href="http://www.forumancientcoins.com/numiswiki/view.asp?key=alloy" target="_blank" class="externalLink ProxyLink" data-proxy-href="http://www.forumancientcoins.com/numiswiki/view.asp?key=alloy" rel="nofollow">alloy</a> components.”&nbsp; <a href="http://www.ptolemybronze.com/" target="_blank" class="externalLink ProxyLink" data-proxy-href="http://www.ptolemybronze.com/" rel="nofollow">PtolemAE</a></p><p><br /></p><p>“Cobalt and iron are closely associated with copper ore deposits and can be quite difficult to completely separate out during the refining process. … Additionally these trace elements might help determine the location on the copper deposits used in this coinage. Do the coins with magnetic properties come from the same region?”&nbsp; Cameron&nbsp; <a href="http://www.forumancientcoins.com/board/index.php?topic=49787.25" target="_blank" class="externalLink ProxyLink" data-proxy-href="http://www.forumancientcoins.com/board/index.php?topic=49787.25" rel="nofollow">http://www.forumancientcoins.com/board/index.php?topic=49787.25</a></p><p><br /></p><p>Any other info that might be appreciated by people searching Coin Talk for information on magnetic ancient bronzes?[/QUOTE]</p><p><br /></p>

Your name or email address:

Do you already have an account?

• No, create an account now.
• Yes, my password is:
• Forgot your password?

Stay logged in